The invention relates to a biomass gasification gas purification system and method, and a methanol production system and method, which effectively use biomass as a raw material and may obtain a clean gas raw material available for use as fuel or for production of liquid fuel such as alcohol.
Generally, biomass is biological objects (for example, agricultural products or by-products, wood, plants and the like) available for use as an energy source or an industrial raw material and is generated by action of solar energy, air, water, soil or the like and then is infinitely renewable.
The production of clean energy sources such as gas and methanol for fuel is available by using the biomass described above. In addition, since biomass as waste matter can be processed, it helps to purify the environment and the biomass, which is newly produced, is also grown by photosynthesis while fixing CO2. Since CO2 does not increase in the atmosphere, this leads to restraints on CO2 and is a favorable technique.
Here, as the biomass which is supplied, it is preferable that produced or discarded biomass, which is crushed and dried, be supplied. The biomass in the invention is a biological resource (for example, agricultural products or by-products, wood, plants and the like) available for use as the energy source or the industrial raw material, and for example, plants such as sweet sorghum, napier grass and spirulina, and wood such as Japanese cedar, broad-leaf tree and bark may be used (see Patent Literature 1 and 2, and Non Patent Literature 1).
However, since the gas generated using biomass as the raw material includes fine particles, a tar component, hydrogen sulfide, chlorine or the like, it is not suitable for the gas without modification to synthesize the energy source to liquid fuel and fuel cell using a synthetic catalyst. Thus, as described above, a scheme is devised to remove minor components such as the fine particles, the tar component, the hydrogen sulfide and the chlorine described above, using a gas purification apparatus including a separation apparatus. In the gas as the raw material for obtaining the liquid fuel or the fuel cell described above form the energy source, in practical application, it is necessary for the minor components to be reduced to a permissible content of less than 0.1 mg/Nm3 of tar and less than 0.1 ppm of an S component. However, currently, the biomass gasification system does not lead to a sufficient reduction in the minor components described above.
In addition, a treatment scale using the biomass gasification system described above is hundreds of tons/day and is equivalent to a small scale to a middle scale plant compared to a gasification system using conventional fossil fuel. In a small and middle scale gas treatment system described above, it is desirable to include a simple and cheap gas purification line which is a necessary condition in a so-called decentralization plant. Regarding this point, in the biomass gasification system of the related art, a simple and cheap gas purification line is not realized.
In the related art, a biomass gasification system including separation means such as a cyclone to filter dust from a generated gas which is gasified in a biomass gasification furnace, a cooler cooling the gas from which the dust is filtered, and a gas purification apparatus purifying the gas which is cooled is disclosed (Patent Literature 3).
The gas purification apparatus of the biomass gasification gas of the related art is configured in such a manner that the biomass is temporarily stored and the cooled generated gas passing through the cooler is passed through the gas purification apparatus, the tar component included in the cooled generated gas is absorbed onto the gas purification apparatus and as the purification gas, the tar absorbed biomass, which has absorbed the tar is transported to biomass supply means using transportation means.
Further, a fixed layer type removing apparatus having a remover layer removing the tar component is disclosed (Patent Literature 4).